__d_unalias() should refuse to move mountpoints (ee3efa91) · Commits · e / devices / android_kernel_oneplus_sm7250

fs/dcache.c

+5 −4

Original line number	Diff line number	Diff line
		@@ -2387,14 +2387,13 @@ static struct dentry __d_unalias(struct inode inode,
		struct dentry dentry, struct dentry alias)
		{
		struct mutex m1 = NULL, m2 = NULL;
		struct dentry *ret;
		struct dentry *ret = ERR_PTR(-EBUSY);

		/* If alias and dentry share a parent, then no extra locks required */
		if (alias->d_parent == dentry->d_parent)
		goto out_unalias;

		/* See lock_rename() */
		ret = ERR_PTR(-EBUSY);
		if (!mutex_trylock(&dentry->d_sb->s_vfs_rename_mutex))
		goto out_err;
		m1 = &dentry->d_sb->s_vfs_rename_mutex;
		@@ -2402,8 +2401,10 @@ static struct dentry __d_unalias(struct inode inode,
		goto out_err;
		m2 = &alias->d_parent->d_inode->i_mutex;
		out_unalias:
		if (likely(!d_mountpoint(alias))) {
		__d_move(alias, dentry);
		ret = alias;
		}
		out_err:
		spin_unlock(&inode->i_lock);
		if (m2)